Resonator system as a safety and arming device



United States Patent Ofiice 3,362,332 Patented Jan. 9, 1968 3,362,332RESONATOR SYSTEM AS A SAFETY AND ARMING DEVICE Carl J. Campagnuolo,Chevy Chase, Md., assignor to the United States of America asrepresented by the Secretary of the Army Filed Nov. 2, 1966, Ser. No.591,660 7 Claims. (Cl. 102-81) ABSTRACT OF THE DISCLOSURE A mechanicalprojectile arming mechanism which uses ram air as an activating force.The projectile to be armed has an opening in its nose and a pressuresensitive valve is set within. When the projecticle reaches a certainvelocity and hence the pressure on the valve reaches a certain level,the valve will open and the ram air is transferred to a Helmholtzresonator within the projectile which has a mechanical output. Themechanical output is used to rotate a gear which aligns a firing pinwith a detonator to arm the projectile.

This device relates to the arming of ordance fuzes and in particular toa device which utilizes ram air to arm itself.

Explosive projectiles are intended to damage a designated target inresponse to a firing influence received by the projectile near or at thedesignated target. The firing influence may be produced by impact, as inthe present invention, by a timing device or by a proximity fuze.Maximum safety for the personnel who launch the projectile require theutilization of a highly eflective safetyand-arming device. When theprojectile fuze is in the safe, or unarmed, state it can be handledsafely and is immune to firing influences. When the fuze is in the armedstate it is ready to exploded in response to a firing influence. Thesafety and arming device must dependably keep the projectile unarmeduntil it has travelled a safe distance atter being launched and mustdependably arm the projectile by the time the projectile reaches theregion of an intended target.

It is therefore an object of the present invention to provide aprojectile with an arming device which will arm the projectile away fromthe launching means but before the projectile reaches its target.

A further object of the invention is to arm a projectile using the ramair of the projectile as the power supply.

Another object of the invention is to provide means to arm a projectileafter it has reached a particular velocity.

Still another object of the invention is to utilize the ram air of aprojectile to create mechanical movement in the projectile which willarm the projectile, without the need for an external power source.

Briefly, the present invention utilizes a pressure sensitive valve inthe nose of the projectile to be armed. Ram air at a certain velocity(and hence pressure) opens the valve and is transferred to a Helmholtzresonator which has a mechanical output. The mechanical output is usedto rotate a gear which aligns a firing pin with a detonator to arm theprojectile.

The specific nature of the invention as well as other objects andaspects thereof will clearly appear from the following description andthe accompanying drawing in which:

FIG. 1 is a schematic representation of the arming mechanism inaccordance with the present invention.

FIG. 2 illustrates a latch mechanism employed in the present invention.

FIG. 3 illustrates a gearing element employed in the present invention.

In FIG. 1, a projecticle 10 has a nose portion 11 in which a circularopening 13 is formed. A valve 14 having a circular cross-section isadapted to seat in circular opening 13 to form an air tight seal betweenthe ambient and the interior of the projectile. An O-ring 16 on thecircumference of opening 13 and a taper 15 on the top of valve 14 areone of the conventional ways to seal the interior of the projectile fromambient. However, any efficient sealing means could be used and I do notwish to limit myself to the use of an O-ring. Valve 14 has a stem 17 ofcircular cross-section which is joined to the center of a valve base 18by any conventional joining means available to the skilled mechanic. Ifdesired stem 17 can be made integral with valve 14. Stem 17 houses alatchet-mechanism 19 which houses a post member 21, which is attached tothe walls of stem 17 by any conventional attaching means. A slide 20 hasa groove 24 in it (FIG. 2) which receives the end of post 21 notattached to stem 17. A spring 22 surrounds the end of post 21 attachedto stem 17 and applies a biasing force against a shoulder 25 of :slide20. Stem 17 has a hole 27 in it through which an end 26 of slide 20 canextend. A guide 76 is attached to projectile 10 at a junction 27 and hasa curved section 28, which leads to a flat section 29. A sleeve section30 is perpendicular to and integral with flat section 29 and surroundsstem 17. The sleeve section 30 has a latchet catcher 31, which has anopening 32 (FIG. 2), which receives slide 20 when hole 27 and opening 32are aligned. A left side 62 of guide 76 forms an air passage 33 betweenopening 13 and the lower section of projectile 10. Part of left side 62is a section 34, which is perpendicular to the left side 62 and furtherserves to define air passage 33. Attached to a base 38 of stem 17 is aspring 35, which is attached to projectile 10 by a platform 36. A bleed37 is in the sidewall of projectile 10 below the juncture of platform 36and the sidewall of the projectile and constantly communicates withatmosphere. A support means 39 is attached to the sidewall of projectile10 and by a funnel 40 and a conical section 41 defines a resonatorchamber 42. Attached by conventional means to the bottom of resonatorchamber 42 is a diaphragm 43. Resonator chamber 42 acts as a vibratingdevice in accordance with the principles of la Helmholtz resonator.Briefly, a Helmholtz resonator consists of a defined volume into whichgas enters and leaves by a port leading to the defined volume. Thepressure of gas in the defined volume changes as it is alternatelycompressed and expanded by the influx and efllux of gas through the portcausing resonance within the chamber. A further detailed discussion ofthe Helmholtz resonator can be found in chapter 8 of the second editionof Fundamentals of Acoustics by Kinsler and Frey (published by JohnWiley and Sons, 1962). A drive element 46 is attached by conventionalmeans to diaphragm 43 by a rod 44. A tongue 45 is integral with rod 44while being perpendicular to the rod. The tongue is of triangularcross-section and has a slight taper 46 on its bottom portion forreasons which will become readily apparent. A gear 50 rotates about acenter 51 and over a portion of its circumference has teeth 53. Theteeth (FIG. 3) have a curved top portion 57 and a straight bottomportion 58. A firing pin 49 is on the circumference of gear 50, and isapproximately opposite to the toothed portion of the gear. A primer 46is lodged in a detonator 47 below gear 50.

The initial orientation of firing pin 49 and detonator 46 must beconsidered in determining the number of teeth on gear 50. There must bea predetermined number of teeth to insure that if every toothcontributes to the counterclockwise movement of the gear the firing pinwill be properly aligned with the detonator. If there is an excessnumber of teeth, the firing pin will rotate past the detonaa.) tor whileif there is an insuflicient number of teeth the firing pin will stopshort of the detonator.

Spring 35 can be selected to a particular strength so that valve 14 willnot open under ram pressure till the projectile reaches a designatedvelocity.

Before the projectile is launched, gear 50 is positioned so tongue 45 ison top of tooth '70. When the projectile is launched, spring 35 willinitially hold valve 14 in a seated position with respect to opening 13.As the velocity of the projectile increases, the ram air pressureagainst the top of valve 14 will increase tending to unseat valve 14against the biasing force of spring 35. When the force from the ram airon the top of valve 14 is greater than the biasing force of spring 35,the valve will unseat by stem 17 sliding down sleeve 30. After valve 14-has moved, along with stem 17, in a downward direction a sufiicientdistance hole 27 in the stem will align with hole 32 of the latchetcatcher. Slide will no longer be constrained by the walls of sleeve andunder the urging of spring 22, will enter the latchet catcher, lockingvalve 14 in an unseated position. Ram air will enter the interior ofprojectile 10 and pass through air passage 33 where Part will enterresonator chamber 42. The pressure in the resonator chamber will buildup until it reaches a resonant pressure at which time resonance willresult causing diaphragm 43 to vibrate vigorously in an up and downdirection. As the diaphragm moves down, tongue 45 will also move down.The tongue will slide over the top rounded portion 57 of gear tooth 70.The tooth is not rotated because the rounded portion of the tooth andtaper 46 of the tongue do not provide for positive displacement as therounded portion of the tooth causes the tongue to slide over it. Thesliding of the tongue over the gear tooth results in a slight rightwardmotion of the tongue. After tongue passes the rounded portion of thegear tooth, it will move to the left to about surface 58 since thetongue will no longer be guided to the right by rounded element 57. Thediaphragm will now move in an upward direction with the top of tongue46, catching the flat portion of the gear tooth. This will result in acounterclockwise motion of the gear as indicated by the arrow 60. Indesigning the pitch of the gear teeth, the amplitude of the diaphragmmovement must be taken into account to insure proper displacement of thegear. Gear will continue to be rotated in a counter-clockwise directionuntil the firing pin and the detonator are aligned. At this point, therewill be no further rotation of the gear since the gear will have onlyenough teeth to rotate the gear to align the firing pin and detonator.The projectile will be armed and ready to be detonated upon impact.

It will be apparent that the embodiments shown are only exemplary andthat various modifications can be made in construction and arrangementwithin the scope of the invention as defined in the appended claims.

I claim as my invention:

1. A projectile arming mechanism comprising:

(a) a projectile having walls defining an interior and a nose portionwith an opening therein through which ram air is admitted to saidinterior,

(b) valve means moved by the ram air of said projectile to admit saidram air to said interior of said projectile, said valve means biased toseat in said opening and including;

(i) a head and stem portion, (ii) said head portion seating in saidopening, and

(iii) said stem portion being surrounded by a sleeve and housing alatchet device, said sleeve having latchet means to co-operate with stemlatchet device to lock said valve means when said valve means is movedby said ram air a certain distance,

(0) fluid resonator means in the interior of said projectile operated bysaid ram air, said resonator having a resonator chamber including afluid port and a diaphragm for a base,

(d) means actuated by said resonator means to arm said projectile.

2. A device according to claim 1 wherein the means activated by saidresonator means include:

(a) a rotating device,

(b) a firing pin carried by said rotating device, and

(c) a primer located below said rotating device.

3. A device according to claim 2 wherein:

(a) a rod is attached to said diaphragm,

(b) a tongue is extended from said rod,

(c) said rotating device carries a plurality of gear teeth,

(d) said tongue is positioned to move said gear teeth.

4. A device according to claim 3 wherein:

(a) said gear teeth each have a rounded and flat portion,

and

(b) said tongue has tapered and flat portion to cooperate with saidrounded and flat portion of each of said gear teeth to rotate said gear.

5. A projectile arming mechanism comprising:

(a) a projectile having walls defining an interior,

(b) valve means moved by the ram air of said projectile to admit saidram air to said interior of said projectile,

(c) fluid resonator means in the interior of said projectile operated bysaid ram air, said resonator having a resonator chamber, and

(d) means actuated by said resonator means to arm said projectile, saidmeans including;

(i) a rotating device,

(ii) a firing pin carried by said rotating device,

and

(iii) a primer located below said rotating device.

6. A device according to claim 5 wherein:

(a) a rod is attached to said diaphragm,

(b) a tongue extends from said rod,

(0) said rotating device carries a plurality of gear teeth,

(d) said tongue is positioned to move said gear teeth.

'7. A device according to claim 6 wherein:

(a) said gear teeth each have a rounded and flat portion, and

(b) said tongue has tapered and flat portion to cooperate with saidrounded and flat portion of each of said gear teeth to rotate said gear.

References Cited UNITED STATES PATENTS 1,309,770 7/1919 Newell 102-821,850,196 3/1932. Bardsley 102-81 2,362,121 11/1944 Doe et al. 102-702,516,890 8/1950 Liljegren 102-70 2,895,063 7/1959 Morris 10270.2

BENJAMIN A. BORCHELT, Primary Examiner.

G. H. GLANZMAN, Assistant Examiner,

